There are several pitch phenomena described in the literature which seem to be behaviorally related and may or may not be mediated by the same physiological mechanism. Sensations of pure tone pitch, complex tone pitch, periodicity pitch, repetition pitch and noise envelope pitch all seem to have in common that they can be used to convey musical information such as melodies or melodic intervals. Despite this common behavioral feature, these phenomena have from a theoretical viewpoint been treated quite separately, and models or theories developed to account for them have often little in common. A theoretical and experimental research plan is proposed in which several pitch phenomena are examined experimentally, particularly pure tone, complex tone and noise envelope pitch, and in which an attempt will be made to provide a common theoretical account for observed behavior. The ultimate goal is a comprehensive theory of pitch perception.